1. Field of the Invention
The present application generally relates to correcting data retrieved from a storage medium, and more particularly to using redundancy blocks to correct errors in data retrieved a storage medium.
2. Related Art
Data is stored in a storage device by writing the data to a storage medium in the storage device. The stored data can be later retrieved from the storage device by reading the data from the storage medium. However, for a number of reasons, an error may exist in the data retrieved from the storage device, meaning that the stored data cannot be retrieved or is different from the data originally stored on the storage medium. For example, a portion of the stored data on the storage medium may degenerate over time such that the portion of the stored data cannot be properly read at a later time.
In a conventional technique to correct such errors, a set of redundancy blocks is generated for the data and stored with the data in the storage medium. When the stored data is later retrieved and an error is detected, the redundancy blocks are used to correct the retrieved data. Typically all of the redundancy blocks in the set of redundancy blocks are used to correct the retrieved data regardless of the size of the error in the retrieved data. Accessing all of the redundancy blocks, however, consumes access time to the storage medium, increases the numbers of calculations that need to be performed, and increases correction time.